A branch junction connector can be based on a bus bar wiring system through which wiring harness terminals are interconnected. To this end, the bus bar wiring is formed by cutting thin bent metallic sheets into narrow strips. Other connecting systems are based on printed circuit boards on which wiring is added in the form of copper layers. Branch junction boxes comprising the aforementioned bus bar wiring system can withstand strong electric currents. However, the cutting and forming of the thin metallic sheets is labor intensive and the approach is not amenable to a speeding up the assembly of the junction box.
On the other hand, in the branch junction box comprising the print circuit, it is relatively easy to form the circuit wiring system and miniaturization is possible. However, the printed wire circuit cannot withstand high currents.
As a way of solving the above-mentioned problem, a branch junction box has been described in JP-A-1 202 109. When configured for connecting terminals, the branch junction box combines a bus bar wiring system with high current capacity connections and a sheet wiring system using a flexible printed circuit (FPC) for weak and moderate currents. In this way, means are provided for accommodating the large currents whilst enabling the dimensions of the box to remain reasonably small.
In branch junction boxes comprising FPC sheet wiring systems, connecting terminals are formed by reinforcing FPC terminals that are integrally formed by the FPC sheet. FIG. 9 shows an example of such a connecting terminal, wherein connector housing 10 on branch junction box 11 is integrally provided with reinforcing wall 12, the latter then being covered with FPC terminal 13.
FIG. 10 shows another example of a connecting terminal in which protruding portion 14 is provided at an internal face of connector housing 10, while FPC terminal 13 is provided with hole 13a for receiving the protruding portion. Thus, FPC terminal 13 is fixed by engagement of protruding portion 14 by hole 13a.
As shown in FIGS. 9 and 10, connecting terminal 15 of a wiring harness is formed by elastically bending a narrow metallic band along part of its length. This terminal 15 is inserted into connector housing 10 and connected to a connecting terminal therein.
However, the FPC sheet in such a known branching junction box 11 is thin and easily bent, so that it is difficult to secure it reliably in branch junction box 11. Moreover, when box 11 is composed of a lower case and an upper case (not shown in figures), the FPC sheet may be nipped between the two when they are assembled, with the risk of cutting off a portion of the sheet wiring.
Moreover, FPC terminal 13, being integral with an FPC sheet, has to be thin and soft. This makes it difficult to work the terminal through and insert it securely into connector housing 10. Further, the electrical connection between FPC terminal 13 on the side of branch junction box 11 and connecting terminal 15 on the side of the wiring harness requires a certain amount of resilience. In such a structure, when branch junction box 11 is deformed by heat, such as is generated within a vehicle, especially at the level of connector housing 10, proper electrical contact may no longer be ensured between FPC terminal 13 and connecting terminal 15.
It is, therefore, an object of the present Invention to solve each of the above-mentioned problems by providing an interconnecting system for wiring harnesses and a branch junction box containing the latter, in which a thin and foldable FPC sheet is easily fixed without being impaired and in which connecting terminals are easily installed, thereby enabling proper electric contact with a wiring harness.